Extinction Research Articles

Dominance and rarity in tree communities across the globe: Patterns, predictors and threats

AbstractAimEcological and anthropogenic factors shift the abundances of dominant and rare tree species within local forest communities, thus affecting species composition and ecosystem functioning. To inform forest and conservation management it is important to understand the drivers of dominance and rarity in local tree communities. We answer the following research questions: (1) What are the patterns of dominance and rarity in tree communities? (2) Which ecological and anthropogenic factors predict these patterns? And (3) what is the extinction risk of locally dominant and rare tree species?LocationGlobal.Time period1990–2017.Major taxa studiedTrees.MethodsWe used 1.2 million forest plots and quantified local tree dominance as the relative plot basal area of the single most dominant species and local rarity as the percentage of species that contribute together to the least 10% of plot basal area. We mapped global community dominance and rarity using machine learning models and evaluated the ecological and anthropogenic predictors with linear models. Extinction risk, for example threatened status, of geographically widespread dominant and rare species was evaluated.ResultsCommunity dominance and rarity show contrasting latitudinal trends, with boreal forests having high levels of dominance and tropical forests having high levels of rarity. Increasing annual precipitation reduces community dominance, probably because precipitation is related to an increase in tree density and richness. Additionally, stand age is positively related to community dominance, due to stem diameter increase of the most dominant species. Surprisingly, we find that locally dominant and rare species, which are geographically widespread in our data, have an equally high rate of elevated extinction due to declining populations through large‐scale land degradation.Main conclusionsBy linking patterns and predictors of community dominance and rarity to extinction risk, our results suggest that also widespread species should be considered in large‐scale management and conservation practices.

The Complex Genetic Legacy of Hybridization and Introgression between the Rare Ocotea loxensis van der Werff and the Widespread O. infrafoveolata van der Werff (Lauraceae).

Hybridization and introgression are complex evolutionary mechanisms that can increase species diversity and lead to speciation, but may also lead to species extinction. In this study, we tested the presence and genetic consequences of hybridization between the rare and Ecuadorian endemic O. loxensis van der Werff and the widespread O. infrafoveolata van der Werff (Lauraceae). Phenotypically, some trees are difficult to identify, and we expect that some might in fact be cryptic hybrids. Thus, we developed nuclear microsatellites to assess the existence of hybrids, as well as the patterns of genetic diversity and population structure in allopatric and sympatric populations. The results revealed high levels of genetic diversity, even in the rare O. loxensis, being usually significantly higher in sympatric than in allopatric populations. The Bayesian assignment of individuals into different genetic classes revealed a complex scenario with different hybrid generations occurring in all sympatric populations, but also in allopatric ones. The absence of some backcrossed hybrids suggests the existence of asymmetric gene flow, and that some hybrids might be more fitted than others might. The existence of current and past interspecific gene flow also explains the blurring of species boundaries in these species and could be linked to the high rates of species found in Ocotea.

Annual progress in global carbon capture, utilization, and storage in 2023

AbstractSince the industrial revolution, global anthropogenic CO2 emissions have surged dramatically to unsustainable levels, resulting in severe issues, such as global warming, extreme weather events, and species extinction. In response to this critical situation, extensive efforts have been undertaken across academia, industry, and policymaking sectors to deploy carbon capture, utilization, and storage (CCUS) technologies. Here, we present the annual summary of global CCUS for the year 2023. We begin by discussing the trends of anthropogenic CO2 emissions and atmospheric CO2 concentrations, and then offer an up‐to‐date summary of progress in academia, industry, and policy, respectively. In academia, we analyze the number and categories of publications and highlight some key breakthroughs. In the industry sector, we meticulously collect and present information on operational commercial carbon‐capture and storage facilities. Furthermore, we elucidate significant policy announcements and reforms across diverse regions. This concise and comprehensive annual report aims to inspire ongoing efforts and collaboration among academia, industry, and policymakers toward advancing carbon neutrality.

Ostracod turnover during the Carnian Pluvial Episode (Late Triassic) in the Western Neotethys

The Carnian Pluvial Episode (CPE) caused a biotic crisis and turnover in terrestrial and marine ecosystems in the Western Neotethyan realm. The expansion of deltaic systems on land and the increased siliciclastic input affected the distribution of benthic ostracods, both nearshore and offshore. Diversity changes of Carnian ostracod faunas from seven successions in the Transdanubian Range (TR), Western Hungary tracked the effects of the CPE, despite its distal hemipelagic depositional setting and position within an intraplatform basin. At the onset of CPE in the early Julian 2, the composition of the studied benthic ostracod assemblage was similar to that of the late Julian 1 communities albeit with decreased abundance of smooth bairdiids and healdiids. The ratio of healdiids and smooth bairdiids is likely related to the detrital supply with bairdiids colonizing primarily in intervals with decreased terrestrial input and carbonate platform progradation. During the maximum expansion of CPE in late Julian 2, the predominance of platycopid Bektasia indicates a shallowing trend, infilling of the Carnian basins and stressed environment due to clastic input and salinity stress. The Julian–Tuvalian boundary is characterized by high extinction rates among marine invertebrates simultaneously with the occurrence of a unique low diversity but abundant brackish water ostracod community with Simeonella and Renngartenella that can be traced along the entire Western Neotethys and northern Gondwana shelf. The appearance of this community is primarily linked to salinity variations during the CPE and the formation of restricted basin habitats in the TR with water stratification where the special community lived or was transported there with storms or river outflow. During the Tuvalian, fully open marine conditions were re-established with increased carbonate productivity in the platforms, favouring the colonization of stable shallow marine habitats with the appearance of ornate bairdiids in the ostracod faunas.

Long-term biotic homogenization in the East African Rift System over the last 6 million years of hominin evolution.

Eastern Africa preserves the most complete record of human evolution anywhere in the world but we have little knowledge of how long-term biogeographic dynamics in the region influenced hominin diversity and distributions. Here, we use spatial beta diversity analyses of mammal fossil records from the East African Rift System to reveal long-term biotic homogenization (increasing compositional similarity of faunas) over the last 6 Myr. Late Miocene and Pliocene faunas (~6-3 million years ago (Ma)) were largely composed of endemic species, with the shift towards biotic homogenization after ~3 Ma being driven by the loss of endemic species across functional groups and a growing number of shared grazing species. This major biogeographic transition closely tracks the regional expansion of grass-dominated ecosystems. Although grazers exhibit low beta diversity in open environments of the Early Pleistocene, the high beta diversity of Mio-Pliocene browsers and frugivores occurred in the context of extensive woody vegetation. We identify other key aspects of the Late Cenozoic biogeographic development of eastern Africa, their likely drivers and place the hominin fossil record in this context. Because hominins were undoubtedly influenced by many of the same factors as other eastern African mammals, this provides a new perspective on the links between environmental and human evolutionary histories.

Effects of High Salinity and Water Stress on Wetland Grasses from the Spanish Mediterranean Coast.

The impacts of climate change are reaching unprecedented levels, heightening the risk of species loss and ecosystem service degradation. Wetlands, highly threatened ecosystems, serve vital ecological functions by capturing carbon, filtering water, and harbouring diverse wildlife. Coastal wetlands encounter many challenges, such as increased drought periods and escalating salinity levels, severely impacting plant biodiversity. Assessing how plants respond to various environmental stress factors is imperative for devising successful conservation strategies. In the present study, we examined three representative grass species found in various habitats within the Albufera Natural Park, close to the city of Valencia on the Spanish Mediterranean coast: Imperata cylindrica, Phragmites australis, and Saccharum ravennae. High salinity and water stress conditions were induced by subjecting the plants to irrigation with solutions containing 200, 400, 600, and 800 mM NaCl or withholding irrigation altogether to mimic coastal flooding and drought scenarios. The treatments were maintained until noticeable wilting of the plants occurred, at which point a range of stress biomarkers were determined, including photosynthetic pigments, ions, osmolytes, oxidative stress markers, and antioxidant metabolites, as well as antioxidant enzyme activities. Saccharum ravennae displayed the highest sensitivity to salt stress, whereas I. cylindrica appeared to be the most tolerant. The primary salinity tolerance mechanism observed in I. cylindrica and P. australis was a blockage of ion transport from the root zone to the aerial part, together with the salt-induced accumulation of proline and soluble sugars to high concentrations in the former. No significant effects of the water deficit treatment on the growth or biochemical parameters were observed for any of the analysed species. These findings offer valuable information for the effective management and conservation of coastal wetlands facing the challenges posed by climate change.

A Review on Adaptive Responses of Salamanders to Climate Change

Extinction rates of salamanders are predicted to rise exponentially under rapidly changing environmental conditions. Due to a wide range of anthropogenic activities, the populations of salamanders are highly threatened. The previous published data indicate that salamanders have adapted various plastic responses to acclimatize to the changing environment. These plastic responses help them to buffer the adverse effects of changing environments and also allow them to adapt to new habitats. The objectives of this review paper are to explore the impact of changing climate on salamanders, to elucidate the diverse strategies they employ to mitigate these challenges, and to evaluate the limitations and evolutionary significance of these measures. Additionally, this study will endeavor to forecast whether these adaptive changes are sufficient to address the evolving climate conditions.

Diversity Species and Structure of Mangrove Vegetation in Conservation Forest and Angke Nature Park North Jakarta

Mangrove is important life support ecosystems in coastal and marine areas that have bio-ecological and socio-economic functions. Mangroves are found in tidal areas that have the ability to grow in salty waters and have a role as a barrier to abrasion. Mangrove plants have special adaptability to the environment such as adaptation to low oxygen levels, high salinity and less stable soils. Indonesia has the largest mangrove ecosystem and the highest biodiversity in the world. This study aims to determine the index of diversity and structure of mangrove communities in Hutan Lindung Angke-Kapuk (HLAK) and Taman Wisata Angke (TWA) Angke-Kapuk which is divided into 11 points. The research was carried out on November 15 to 30, 2021 using purposive sampling techniques based on the representation element, which took 5% of the total area and the shape of a square plot with a size of 50x50 meters. The results showed that 11 family, 12 genus and 15 species of mangroves were found, the type was divided into 8 species of true mangroves and 7 species of mangroves followed. The extinction rate of mangrove species in HLAK and TWA Angke-Kapuk amounted to 1.25. The level of type similarity between research points in the HL Angke-Kapuk and TWA Angke Kapuk areas in 2020 and 2021, showed a slight change in the level of type similarity at each point. The dominant type of seedling and sapling tree level is the Avicennia marina type. Mangrove diversity index (H’) in the area of HLAK and TWA Angke Kapuk is 1.6.

Convergent evolution toward a slow pace of life predisposes insular endotherms to anthropogenic extinctions.

Island vertebrates have evolved a number of morphological, physiological, and life history characteristics that set them apart from their mainland relatives. However, to date, the evolution of metabolism and its impact on the vulnerability to extinction of insular vertebrates remains poorly understood. This study used metabolic data from 2813 species of tetrapod vertebrates, including 695 ectothermic and 2118 endothermic species, to reveal that island mammals and birds evolved convergent metabolic strategies toward a slow pace of life. Insularity was associated with shifts toward slower metabolic rates and greater generation lengths in endotherms, while insularity just drove the evolution of longer generation lengths in ectotherms. Notably, a slow pace of life has exacerbated the extinction of insular endemic species in the face of anthropogenic threats. These findings have important implications for understanding physiological adaptations associated with the island syndrome and formulating conservation strategies across taxonomic groups with different metabolic modes.

A deep connection among the natural resources, technical progress, efficient energy and sustainability: The mediating role of governance

Many changes in the environment are causing worry among people all around the world. Several variables are at play here, including climate change, desertification, deforestation, coastal ecosystem erosion, land degradation, excessive fishing, extinction of species, and biodiversity loss. These problems, according to many observers, are the long-term, cumulative effect of human activity on the environment, which has significantly altered Earth's surface. Society and the economy cannot be improved without using natural resources. Yet, environmental deterioration and resource depletion have resulted from unsustainable usage, putting human and environmental health at risk. Reducing carbon emissions is often believed to depend on technological advancements. Using data from 2000 to 2021, this research intends to examine the 20 Emerging economies' CO₂ emissions concerning its potential drivers, including conservation of energy and materials, technical innovation, and governance. We provide more comprehensive evaluations of various multivariate econometric methods, including various cointegration approaches (e.g., Padroni and Kao), long-run estimates of fixed and random effects, robustness checks using cointegration regressions (e.g., FMOLS and DOLS), and the frequency-domain PMG method. Although technical innovation and good governance can improve the environmental quality of emerging economies, our findings demonstrate that energy and land conservation reduce CO2 emissions. Furthermore, carbon emissions are adversely affected by the governance interaction term (GOV) with natural resources. Policymakers may use these results to help Emerging Markets achieve sustainable development.

Genomic data provides insights into the evolutionary history and adaptive differentiation of two tetraploid strawberries.

Over the decades, evolutionists and ecologists have shown intense interest in the role of polyploidization in plant evolution. Without clear knowledge of the diploid ancestor(s) of polyploids, we would not be able to answer fundamental ecological questions such as the evolution of niche differences between them or its underlying genetic basis. Here, we explored the evolutionary history of two Fragaria tetraploids, Fragaria corymbosa and Fragaria moupinensis. We de novo assembled five genomes including these two tetraploids and three diploid relatives. Based on multiple lines of evidence, we found no evidence of subgenomes in either of the two tetraploids, suggesting autopolyploid origins. We determined that Fragaria chinensis was the diploid ancestor of F. corymbosa while either an extinct species affinitive to F. chinensis or an unsampled population of F. chinensis could be the progenitor of F. moupinensis. Meanwhile, we found introgression signals between F. chinensis and Fragaria pentaphylla, leading to the genomic similarity between these two diploids. Compared to F. chinensis, gene families related to high ultraviolet (UV)-B and DNA repair were expanded, while those that responded towards abiotic and biotic stresses (such as salt stress, wounding, and various pathogens) were contracted in both tetraploids. Furthermore, the two tetraploids tended to down-regulate defense response genes but up-regulate UV-B response, DNA repairing, and cell division gene expression compared to F. chinensis. These findings may reflect adaptions toward high-altitude habitats. In summary, our work provides insights into the genome evolution of wild Fragaria tetraploids and opens up an avenue for future works to answer deeper evolutionary and ecological questions regarding the strawberry genus.

Pseudopus pannonicus (Squamata), the largest known anguid lizard-Redescription of the type material and new specimens from the Neogene and Quaternary of Hungary and Poland.

Herein, we revise the material of the extinct taxon Pseudopus pannonicus from Central Europe, the largest known anguid lizard and iconic member of herpetofaunas from the Upper Cenozoic of Europe. The geographical position of Polgárdi 2, the type locality of P. pannonicus, as well as several other closely located important localities make Central Europe a valuable area of high interest for studies regarding European Cenozoic palaeoherpetological assemblages. We clarified the nature of the type material of Pseudopus pannonicus, showing that it consisted not only of the five specimens originally figured. Instead, the syntype series also includes a considerable number of specimens from Polgárdi 2 that were only described or figured 12 years after the original description of P. pannonicus. Detailed osteological descriptions are provided for specimens from the type series and Polish specimens, with the aid of high-resolution imaging (SEM and μCT scanning), and intraspecific variability is discussed. The articular surface with the lappet of the parietal overlapping the frontal is discussed as a character potentially relevant for the diagnosis of P. pannonicus. We updated the identification of several specimens of P. pannonicus and discussed the biogeographic implications of such revisions. In Poland, P. pannonicus is an abundant component of Neogene and early Quaternary herpetofaunas, known with certainty from the Middle Miocene of Przeworno (the oldest known occurrence of the species globally), the Early-Late Pliocene of Węże I, the Late Pliocene of Rębielice Królewskie I, the Late Pliocene of Węże II, and the Early Pleistocene of Kadzielnia (one of the youngest occurrences documented globally). An indeterminate anguine with Anguis affinities is newly reported from Rębielice Królewskie II. The taxonomic status of other large anguids from the Neogene of Europe is discussed and we conclude that most are junior synonyms of P. pannonicus. We also show that another purported synonym, that is, Ophisaurus intermedius from the Early Pleistocene of Romania, is instead a nomen nudum. We conducted phylogenetic analyses (18 taxa, 65 characters) to understand the relationship of P. pannonicus relative to other anguid representatives and anguid-related group (i.e., glyptosaurids). A single most parsimonious tree (length: 134 steps) was recovered. The clade Pseudopus is stable, comprising the two distinct sister subclades [Pseudopus laurillardi + Pseudopus ahnikoviensis] and [Pseudopus pannonicus + Pseudopus apodus]. These phylogenetic results are in accordance with previously published works.

Spatial decoupling of taxon richness, phylogenetic diversity and threat status in the megagenus Erica (Ericaceae).

Estimates of the number of vascular plant species currently under threat of extinction are shockingly high, with the highest extinction rates reported for narrow-range, woody plants, especially in biodiversity hotspots with Mediterranean and tropical climates. The large genus Erica is a prime example, as a large proportion of its 851 species, all shrubs or small trees, are endemic to the Cape Floristic Region (CFR) of South Africa. Almost two hundred are known to be threatened and a further hundred are 'Data Deficient'. We need to target conservation efforts and research to fill the most problematic knowledge gaps. This can be especially challenging in large genera, such as Erica, with numerous threatened species that are closely related. One approach involves combining knowledge of phylogenetic diversity with that of IUCN threat status to identify the most Evolutionarily Distinct and Globally Endangered (EDGE) species. We present an expanded and improved phylogenetic hypothesis for Erica (representing 65% of described species diversity) and combine this with available threat and distribution data to identify species and geographic areas that could be targeted for conservation effort to maximise preservation of phylogenetic diversity (PD). The resulting 39 EDGE taxa include 35 from the CFR. A further 32 high PD, data deficient taxa are mostly from outside the CFR, reflecting the low proportion of assessed taxa outside South Africa. The most taxon-rich areas are found in the south-western CFR. They are not the most phylogenetically diverse, but do include the most threatened PD. These results can be cross-referenced to existing living and seed-banked ex situ collections and used to target new and updated threat assessments and conservation action.

Trade-off and chaotic dynamics in a two-prey one-predator model with refuge, environmental noise and seasonal effects

In nature, poisonous prey species have developed toxins as an attack against predators. However, predator’s decisions to consume aposematic toxic prey are not solely determined by their toxicity. Predators often weigh the costs of ingesting toxins against the benefits of obtaining nutrients, with body size acting as a significant cue. In terms of avoiding predation, prey commonly respond by seeking refuge, a behavior that fluctuates considerably due to seasonality and environmental variability. In this study, we integrate these factors into the dynamics of two prey and one predator model. We explore the cost of fear to illustrate the trade-off dynamics of prey, and we adjust the predator’s death rate by integrating a function that serves predator loss resulting from encounters with toxic prey. Our model demonstrates bistability as a consequence of hysteresis effect and undergoes various bifurcations, including saddle–node, Hopf, Bautin, and cusp bifurcations. We observe that increasing prey refuge and reducing the level of fear contribute to system stabilization, yet chaotic behavior persists with respect to both parameters. While seasonality can introduce stability and periodicity, it may also give rise to complex and unpredictable dynamics. We comprehend that the system might undergo transitions through multiple periodic cycles as a result of changes in the degree of seasonality, yet it eventually settles into a periodic solution. Furthermore, our analysis using the stochastic model reveals that low noise levels maintain species densities close to deterministic equilibrium, whereas high noise levels result in broader dispersion or even extinction of species. The information presented in this article may help readers understand the biological knowledge gained by investigating interactions between predators and prey.

Species pool and soil properties in mangrove habitats influence the species-immigration process of diazotrophic communities across southern China.

Microbial immigration is an ecological process in natural environments; however, the ecological trade-off mechanisms that govern the balance between species extinction and migration are still lacking. In this study, we investigated the mechanisms underlying the migration of diazotrophic communities from soil to leaves across six natural mangrove habitats in southern China. The results showed that the diazotrophic alpha and beta diversity exhibited significant regional and locational variations. The diazotrophic species pool gradually increased from the leaves to nonrhizosphere soil at each site, exhibiting a vertical distribution pattern. Mantel test analyses suggested that climate factors, particularly mean annual temperature, significantly influenced the structure of the diazotrophic community. The diazotrophic community assembly was mainly governed by dispersal limitation in soil and root samples, whereas dispersal limitation and ecological drift were dominant in leaves. Partial least squares path modeling revealed that the species pool and soil properties, particularly the oxidation-reduction potential and pH, were closely linked to the species-immigration ratio of diazotrophic communities. Our study provides novel insights for understanding the ecological trait diversity patterns and spread pathways of functional microbial communities between below- and aboveground habitats in natural ecosystems.IMPORTANCEEnvironmental selection plays key roles in microbial transmission. In this study, we have provided a comprehensive framework to elucidate the driving patterns of the ecological trade-offs in diazotrophic communities across large-scale mangrove habitats. Our research revealed that Bradyrhizobium japonicum, Marinobacterium lutimaris, and Agrobacterium tumefaciens were more abundant in root-associated soil than in leaves by internal and external pathways. The nonrhizospheric and rhizospheric soil samples harbored the most core amplicon sequence variants, indicating that these dominant diazotrophs could adapt to broader ecological niches. Correlation analysis indicated that the diversities of the diazotrophic community were regulated by biotic and abiotic factors. Furthermore, this study found a lower species immigration ratio in the soil than in the leaves. Both species pool and soil properties regulate the species-immigration mechanisms of the diazotrophic community. These results suggest that substantial species immigration is a widespread ecological process, leading to alterations in local community diversity across diverse host environments.

Astragalus endopterus (Fabaceae), a species purported as extinct, found in northern Arizona, U.S.A.

Astragalus endopterus (Barneby) Barneby, listed as an extinct species in a recent Conservation Biology paper (Knapp et al. 2021) was found in abundance after three hours of targeted searching. Continued searches revealed thousands of plants. Our work has doubled the known range of the species. Astragalus endopterus seems to mostly occur on sheetwash deposits composed of particles derived mostly from windblown sands along with a component of clay probably derived from the Chinle Formation. We have no indications that the species may have been in decline or was ever on the verge of extinction.

The Effects of Climate Change on the Distribution Pattern of Species Richness of Endemic Wetland Plants in the Qinghai-Tibet Plateau.

Wetland ecosystems in the Qinghai-Tibet Plateau (QTP), the region with the richest biodiversity and the most important ecological barrier function at high altitudes, are highly sensitive to global change, and wetland plants, which are important indicators of wetland ecosystem structure and function, are also threatened by wetland degradation. Therefore, a comprehensive study of changes in the geographical distribution pattern of plant diversity, as well as species loss and turnover of wetlands in the QTP in the context of global climate change is of great importance for the conservation and restoration of wetland ecosystems in the QTP. In this study, species turnover and loss of 395 endemic wetland plants of the QTP were predicted based on the SSP2-4.5 climate change scenarios. The results showed that there were interspecific differences in the effects of climate change on the potential distribution of species, and that most endemic wetland plants would experience range contraction. Under the climate change scenarios, the loss of suitable wetland plant habitat is expected to occur mainly in parts of the southern, north-central and north-western parts of the plateau, while the gain is mainly concentrated in parts of the western Sichuan Plateau, the Qilian Mountains, the Three Rivers Source Region and the northern Tibetan Plateau. Overlaying the analysis of priority protected areas with the established protected areas in the QTP has resulted in the following conservation gaps: the eastern Himalayan region, midstream of the Yarlung Zangbo River, the transition zone between the northern Tibetan Plateau and the Hengduan Mountains, Minshan-Qionglai mountain, Anyemaqen Mountains (southeast) to Bayankala (southeast) mountains, the southern foothills of the Qilian Mountains and the northern Tibetan Plateau region. In the future, the study of wetland plant diversity in the QTP and the optimisation of protected areas should focus on the conservation gaps. This study is of great importance for the study and conservation of wetland plant diversity in the QTP, and also provides a scientific basis for predicting the response of wetland plants to climate change in the QTP.

Crime control of illegal wildlife trade in Poland

Since Poland joined the European Union, it has become, after the US, the second-largest market for live animal specimens protected by the provisions of the Washington Convention. In addition, it is a transit country for a significant number of specimens (live plants or animals, or products derived from them) destined for buyers in Western Europe, due to Poland's eastern border which is one of the longest EU borders and at the same time the first in the way of illegal wildlife trade [Drzazga, 2020]. The effectiveness of international efforts to counter this phenomenon and its global consequences strongly depends on the actions taken by individual countries that are exporters or importers of extinct and endangered species. That is why it is so important to raise the quality of social control of this phenomenon also in Poland. The main purpose of the article is to present the results of qualitative research on social control of illegal wildlife trade in Poland. Before discussing them, the necessary terminological clarifications will be introduced and the reasons for addressing the topic will be presented.

Exploring the causes underlying the latitudinal variation in range sizes: Evidence for Rapoport's rule in spiny lizards (genus Sceloporus).

Species' range size is a fundamental unit of analysis in biodiversity research, given its association with extinction risk and species richness. One of its most notable patterns is its positive relationship with latitude, which has been considered an ecogeographical rule called Rapoport's rule. Despite this rule being confirmed for various taxonomic groups, its validity has been widely discussed and several taxa still lack a formal assessment. Different hypotheses have been proposed to explain their potential mechanisms, with those related to temperature and elevational being the most supported thus far. In this study, we employed two level of analyses (cross-species and assemblage) to investigate the validity of Rapoport's rule in spiny lizards (genus Sceloporus). Additionally, we evaluated four environmental-related hypotheses (minimum temperature, temperature variability, temperature stability since the last glacial maximum, and elevation) posed to explain such pattern, contrasting our results to those patterns expected under a null model of range position. Our results provided support for Rapoport's rule at both levels of analyses, contrasting with null expectations. Consistently, minimum temperature and elevation were the most relevant variables explaining the spatial variation in range size. At the cross-species level, our null simulations revealed that both variables deviated significantly from random expectations. Conversely, at the assemblage level, none of the variables were statistically different from the expected relationships. We discussed the implication of our findings in relation to the ecology and evolution of spiny lizards.

Об элементных фундаментах опор высоковольтных линий

Purpose: to substantiate the possibility of using the foundations of supports of high-voltage lines in the form of dispersed horizontal elements combined into a single structure for the perception of alternating loads. To determine by experimental and computational methods the effect of the mutual displacement of elements in the form of an increase in the bearing capacity of foundations and a decrease in their deformations under the influence of pressing and pulling loads. To show the possibility of replacing slab foundations of supports of high-voltage lines with structures made of prefabricated elements to reduce the volume and weight of products transported from the factory. Methods: application of the moire photogrammetric method to assess the development of soil compaction zones and angular deformations of the soil base in a tray with a glass wall under models of slab and elemental foundations. Using the method of boundary integral equations to obtain the dependence of precipitation on the step of elements for flexible and rigid foundations. Results: the effect of mutual influence of foundation elements during their convergence and dispersal in the form of a change in the stress-strain state in their base is illustrated. Differences in the depths of the distribution of compaction zones and areas of development of angular deformations are revealed. Quantitative data on the precipitation of slab and elemental foundations and the influence of the depth of the roof of the solid underlying layer on them have been obtained. Graphical dependences of the relationship of sediment elements with the distance (step) between them are presented. The effect of the division of the foundation on the rate of extinction of marginal tangential stresses in the base is shown. An illustration is made of an increase in the volume and surface area of the bulging body of the elemental foundation, which leads to an increase in its bearing capacity compared to the slab one when calculating for pulling out. Practical importance: the effectiveness of the use of an element foundation in comparison with the paid option in reducing the parameters of the stress-strain state of the base and facilitating logistical tasks during construction is shown. The experimental and computational methods used can be recommended for further refinement of the parameters of the elemental foundations.